Volume Does Not Increase With Speed

Volume does not increase with speed

1. Verify the (SVC) mode setting in the navigation or audio unit sound set-up.

Is the (SVC) set to off?

YES - Change the setting to "Mid" and reset.

NO - Go to step 2.

2. Do the self-diagnostic function for the vehicle speed pulse indication.

Does the self-diagnostic function indicate a VSP signal?

YES - Substitute a known-good navigation or audio unit and retest. If the symptom/indication goes away, replace the original navigation or audio unit.

NO - Go to step 3.

3. Check for B-CAN codes with the HDS.

Are there any gauge module B-CAN codes?

YES - Go to test mode A.

NO - Go to step 4.

4. Inspect the VSP signal in the navigation system.

Does the VSP change from O to 1 when the vehicle is moving?

YES - Substitute a known-good audio unit, then retest the VSP signal in the audio self-diagnostic test. If the speed is shown, replace the original audio unit. If so speed is shown, substitute a known-good navigation unit.

NO - Inspect the VSP circuit.